Oxtellar XR

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Taking oxcarbazepine with other drugs that make you sleepy can worsen this effect. Ask your doctor before taking a sleeping pill, narcotic medication, muscle relaxer, or medicine for anxiety, depression, or seizures.

Many drugs can interact with oxcarbazepine. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide. Tell your doctor about all your current medicines and any medicine you start or stop using.

• If you have an allergy to oxcarbazepine or any other part of Oxtellar XR (oxcarbazepine extended-release tablets).
• If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
• If you have liver disease.
• If you are breast-feeding or plan to breast-feed.

This is not a list of all drugs or health problems that interact with this medicine.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take Oxtellar XR with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Signs of low sodium levels like headache, trouble focusing, memory problems, feeling confused, weakness, seizures, or change in balance.
• Signs of infection like fever, chills, very bad sore throat, ear or sinus pain, cough, more sputum or change in color of sputum, pain with passing urine, mouth sores, or wound that will not heal.
• Signs of liver problems like dark urine, feeling tired, not hungry, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes.
• Signs of kidney problems like unable to pass urine, change in how much urine is passed, blood in the urine, or a big weight gain.
• Shortness of breath, a big weight gain, or swelling in the arms or legs.
• Swollen gland.
• Very bad muscle pain or weakness.
• Very bad joint pain or swelling.
• Feeling confused.
• Not able to focus.
• Change in speech.
• Change in eyesight.
• Chest pain or pressure.
• Feeling very tired or weak.
• If seizures are worse or not the same after starting Oxtellar XR (oxcarbazepine extended-release tablets).
• Any unexplained bruising or bleeding.
• Not able to control eye movements.
• Memory problems or loss.
• Trouble walking.
• Change in balance.

• Store at room temperature.
• Store in a dry place. Do not store in a bathroom.
• Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
• Check with your pharmacist about how to throw out unused drugs.

• If your symptoms or health problems do not get better or if they become worse, call your doctor.
• Do not share your drugs with others and do not take anyone else's drugs.
• Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
• Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
• This medicine comes with an extra patient fact sheet called a Medication Guide. Read it with care. Read it again each time this medicine is refilled. If you have any questions about Oxtellar XR, please talk with the doctor, pharmacist, or other health care provider.
• If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about Oxtellar XR. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using Oxtellar XR.

Review Date: October 4, 2017

Hyponatremia

Clinically significant hyponatremia (sodium <125 mmol/L) may develop during Oxtellar XR® use. Serum sodium levels less than 125 mmol/L have occurred in immediate-release oxcarbazepine-treated patients generally in the first three months of treatment. However, clinically significant hyponatremia may develop more than a year after initiating therapy.

Most immediate-release oxcarbazepine-treated patients who developed hyponatremia were asymptomatic in clinical trials. However, some of these patients had their dose reduced, discontinued, or had their fluid intake restricted for hyponatremia. Serum sodium levels returned toward normal when the dosage was reduced or discontinued, or when the patient was treated conservatively (e.g., fluid restriction). Post-marketing cases of symptomatic hyponatremia have been reported during post-marketing use of immediate-release oxcarbazepine.

Among treated patients in a controlled trial of adjunctive therapy with Oxtellar XR®in 366 adults with complex partial seizures, 1 patient receiving 2400 mg experienced a severe reduction in serum sodium (117 mEq/L) requiring discontinuation from treatment, while 2 other patients receiving 1200 mg experienced serum sodium concentrations low enough (125 and 126 mEq/L) to require discontinuation from treatment. The overall incidence of clinically significant hyponatremia in patients treated with Oxtellar XR®was 1.2%, although slight shifts in serum sodium concentrations from Normal to Low (<135 mEq/L) were observed for the 2400 mg (6.5%) and 1200 mg (9.8%) groups compared to placebo (1.7%). Measure serum sodium concentrations if patients develop symptoms of hyponatremia (e.g., nausea, malaise, headache, lethargy, confusion, obtunded consciousness, or increase in seizure frequency or severity). Consider measurement of serum sodium concentrations during treatment with Oxtellar XR®, particularly if the patient receives concomitant medications known to decrease serum sodium levels (for example, drugs associated with inappropriate ADH secretion).

Anaphylactic Reactions and Angioedema

Rare cases of anaphylaxis and angioedema involving the larynx, glottis, lips and eyelids have been reported in patients after taking the first or subsequent doses of immediate-release oxcarbazepine. Angioedema associated with laryngeal edema can be fatal. If a patient develops any of these reactions after treatment with Oxtellar XR®, discontinue the drug and initiate an alternative treatment. Do not rechallenge these patients with Oxtellar XR®.

Hypersensitivity Reactions in Patients with Hypersensitivity to Carbamazepine

Inform patients who have had hypersensitivity reactions to carbamazepine that approximately 25%-30% of them will experience hypersensitivity reactions with Oxtellar XR®. Question patients about any prior adverse reactions with carbamazepine. Patients with a history of hypersensitivity reactions to carbamazepine should ordinarily be treated with Oxtellar XR® only if the potential benefit justifies the potential risk. Discontinue Oxtellar XR® immediately if signs or symptoms of hypersensitivity develop [see Warnings and Precautions (5.8)].

Serious Dermatological Reactions

Serious dermatological reactions, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), have occurred in both children and adults treated with immediate-release oxcarbazepine use. The median time of onset for reported cases was 19 days. Such serious skin reactions may be life threatening, and some patients have required hospitalization with very rare reports of fatal outcome. Recurrence of the serious skin reactions following rechallenge with immediate-release oxcarbazepine has also been reported.

The reporting rate of TEN and SJS associated with immediate-release oxcarbazepine use, which is generally accepted to be an underestimate due to underreporting, exceeds the background incidence rate estimates by a factor of 3- to 10-fold. Estimates of the background incidence rate for these serious skin reactions in the general population range between 0.5 to 6 cases per million-person years. Therefore, if a patient develops a skin reaction while taking Oxtellar XR®, consider discontinuing Oxtellar XR® use and prescribing another AED.

Association with HLA-B*1502

Patients carrying the HLA-B*1502 allele may be at increased risk for SJS/TEN with Oxtellar XR® treatment.

Human Leukocyte Antigen (HLA) allele B*1502 increases the risk for developing SJS/TEN in patients treated with carbamazepine. The chemical structures of immediate release oxcarbazepine and Oxtellar XR® are similar to that of carbamazepine. Available clinical evidence, and data from nonclinical studies showing a direct interaction between immediate release oxcarbazepine and HLA-B*1502 protein, suggest that the HLA-B*1502 allele may also increase the risk for SJS/TEN with Oxtellar XR®.

The frequency of HLA-B*1502 allele ranges from 2 to 12% in Han Chinese populations, is about 8% in Thai populations, and above 15% in the Philippines and in some Malaysian populations. Allele frequencies up to about 2% and 6% have been reported in Korea and India, respectively. The frequency of the HLA-B*1502 allele is negligible in people from European descent, several African populations, indigenous peoples of the Americas, Hispanic populations, and in Japanese (<1%).

Testing for the presence of the HLA-B*1502 allele should be considered in patients with ancestry in genetically at-risk populations, prior to initiating treatment with Oxtellar XR®. The use of Oxtellar XR® should be avoided in patients positive for HLA-B*1502 unless the benefits clearly outweigh the risks. Consideration should also be given to avoid the use of other drugs associated with SJS/TEN in HLA-B*1502 positive patients, when alternative therapies are otherwise equally acceptable. Screening is not generally recommended in patients from populations in which the prevalence of HLA-B*1502 is low, or in current Oxtellar XR® users, as the risk of SJS/TEN is largely confined to the first few months of therapy, regardless of HLA-B*1502 status.

The use of HLA-B*1502 genotyping has important limitations and must never substitute for appropriate clinical vigilance and patient management. The role of other possible factors in the development of, and morbidity from, SJS/TEN, such as antiepileptic drug (AED) dose, compliance, concomitant medications, comorbidities, and the level of dermatologic monitoring have not been well characterized.

Suicidal Behavior and Ideation

Antiepileptic drugs (AEDs), including Oxtellar XR®, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Monitor patients treated with any AED for any indication for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.

Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behavior for every 530 patients treated. There were four suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide.

The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed.

The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5-100 years) in the clinical trials analyzed. Table 2 shows absolute and relative risk by indication for all evaluated AEDs.

The relative risk for suicidal thoughts or behavior was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications.

Anyone considering prescribing Oxtellar XR® or any other AED must balance the risk of suicidal thoughts or behavior with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge during Oxtellar XR® treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.

Patients, their caregivers, and families should be informed that AEDs increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of the signs and symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts, behavior, or thoughts about self-harm. Behaviors of concern should be reported immediately to healthcare providers.

Withdrawal of AEDs

As with all AEDs, Oxtellar XR® should be withdrawn gradually to minimize the potential of increased seizure frequency.

Multi-Organ Hypersensitivity

Multi-organ hypersensitivity reactions have occurred in close temporal association (median time to detection 13 days: range 4-60) to the initiation of immediate-release oxcarbazepine therapy in adult and pediatric patients. Although there have been a limited number of reports, many of these cases resulted in hospitalization and some were life-threatening. Signs and symptoms of this disorder were diverse; however, patients typically, although not exclusively, presented with fever and rash associated with other organ system involvement. These included the following: hematologic and lymphatic (e.g., eosinophilia, thrombocytopenia, lymphadenopathy, leukopenia, neutropenia, splenomegaly), hepatobiliary (e.g., hepatitis, liver function test abnormalities), renal (e.g., proteinuria, nephritis, oliguria, renal failure), muscles and joints (e.g., joint swelling, myalgia, arthralgia, asthenia), nervous system (e.g., hepatic encephalopathy), respiratory (e.g., dyspnea, pulmonary edema, asthma, bronchospasm, interstitial lung disease), hepatorenal syndrome, pruritus, and angioedema. Because the disorder is variable in its expression, other organ system symptoms and signs, not noted here, may occur. If this reaction is suspected, discontinue Oxtellar XR®and initiate an alternative treatment.

Hematologic Reactions

Rare reports of pancytopenia, agranulocytosis, and leukopenia have been seen in patients treated with immediate-release oxcarbazepine during post-marketing experience. Discontinuation of Oxtellar XR® should be considered if any evidence of these hematologic reactions develops.

Risk of Seizures in the Pregnant Patient

Due to physiological changes during pregnancy, plasma concentrations of the active metabolite of oxcarbazepine, the 10-monohydroxy derivative (MHD), may gradually decrease throughout pregnancy. Monitor patients carefully during pregnancy and through the postpartum period because MHD concentrations may increase after delivery.

Laboratory Tests

Laboratory data from clinical trials suggest that immediate-release oxcarbazepine may be associated with decreases in T4, without changes in T3 or TSH.

Abuse

The abuse potential of Oxtellar XR® has not been evaluated in human studies. Oxtellar XR® is not habit forming, and is not expected to encourage abuse.

Dependence

Intragastric injections of oxcarbazepine to four cynomolgus monkeys demonstrated no signs of physical dependence as measured by the desire to self-administer oxcarbazepine by lever pressing activity.

Mechanism of Action

The pharmacological activity of Oxtellar XR® is primarily exerted through the 10-monohydroxy metabolite (MHD) of oxcarbazepine [see Clinical Pharmacology (12.3)]. The precise mechanism by which oxcarbazepine and MHD exert their antiseizure effect is unknown; however, in vitro electrophysiological studies indicate that they produce blockade of voltage-sensitive sodium channels, resulting in stabilization of hyperexcited neural membranes, inhibition of repetitive neuronal firing, and diminution of propagation of synaptic impulses. These actions are thought to be important in the prevention of seizure spread in the intact brain. In addition, increased potassium conductance and modulation of high-voltage activated calcium channels may contribute to the anticonvulsant effects of the drug. No significant interactions of oxcarbazepine or MHD with brain neurotransmitter or modulator receptor sites have been demonstrated.

Pharmacodynamics

Oxcarbazepine and its active metabolite (MHD) exhibit anticonvulsant properties in animal seizure models. They protected rodents against electrically induced tonic extension seizures and, to a lesser degree, chemically induced clonic seizures, and abolished or reduced the frequency of chronically recurring focal seizures in Rhesus monkeys with aluminum implants. No development of tolerance (i.e., attenuation of anticonvulsive activity) was observed in the maximal electroshock test when mice and rats were treated daily for five days and four weeks, respectively, with oxcarbazepine or MHD.

Pharmacokinetics

Following oral administration, oxcarbazepine is absorbed and extensively metabolized to its pharmacologically active 10-monohydroxy metabolite (MHD), which is responsible for most antiepileptic activity.

In clinical studies of Oxtellar XR®, the elimination half-life of oxcarbazepine was between 7 and 11 hours; the elimination half-life of MHD is between 9 and 11 hours.

In a mass balance study in human, only 2% of total radioactivity in plasma after administration of immediate-release oxcarbazepine was due to unchanged oxcarbazepine, with approximately 70% present as MHD, and the remainder attributable to minor metabolites.

Absorption

Oxtellar XR® administered as a once daily dose is not bioequivalent to the same total dose of the immediate release formulation given twice daily at steady state. Steady state plasma concentrations of MHD are reached within 5 days when Oxtellar XR® is given once daily. At steady state, when 1200 mg Oxtellar XR® was given once daily, MHD Cmax occurred 7 hours post-dose. At steady state, Oxtellar XR® given once daily produced MHD exposures (AUC and Cmax) about 19% lower and MHD minimum concentrations (Cmin) about 16% lower than the immediate-release oxcarbazepine given twice daily when administered at the same 1200 mg total daily dose. When Oxtellar XR® was administered at an equivalent 600 mg single dose (4 × 150 mg tablets, 2 × 300 mg tablets, or 1 × 600 mg tablet), equivalent MHD exposures (AUC) were observed.

Following a single dose of Oxtellar XR® (1 × 150 mg tablets, 1 × 300 mg tablets, or 1 × 600 mg tablet), the pharmacokinetics of MHD are not linear and show greater than dose proportional increase in AUC and less than proportional increase in Cmax: AUC increases 2.4-fold and Cmax increases 1.9-fold with a 2-fold increase in dose.

Effect of Food: Single dose administration of 600 mg Oxtellar XR® following a high fat meal (800 – 1000 calories) produced MHD exposure (AUC) equivalent to that produced under fasting conditions. Peak MHD concentration (Cmax) was about 60% higher and occurred 2 hours earlier under fed conditions than under fasting conditions.

The increase in Cmax, even without a significant change in the overall exposure, should be considered by the prescriber especially during the titration phase, when some adverse reactions are most likely to occur coincidentally with peak levels.

Distribution

The apparent volume of distribution of MHD is 49 L. Approximately 40% of MHD is bound to serum proteins, predominantly to albumin. Binding is independent of the serum concentration within the therapeutically relevant range. Oxcarbazepine and MHD do not bind to alpha-1-acid glycoprotein.

Metabolism

Oxcarbazepine is rapidly reduced by cytosolic enzymes in the liver to MHD, which is primarily responsible for the pharmacological effect of Oxtellar XR®. MHD is metabolized further by conjugation with glucuronic acid. Minor amounts (4% of the dose) are oxidized to the pharmacologically inactive 10,11-dihydroxy metabolite (DHD).

Elimination

Oxcarbazepine is cleared from the body mostly in the form of metabolites which are predominantly excreted by the kidneys. More than 95% of a dose of immediate-release oxcarbazepine appears in the urine, with less than 1% as unchanged oxcarbazepine. Fecal excretion accounts for less than 4% of an administered dose. Approximately 80% of the dose is excreted in the urine either as glucuronides of MHD (49%) or as unchanged MHD (27%); the inactive DHD accounts for approximately 3% and conjugates of MHD and oxcarbazepine account for 13% of the dose.

The half-life of the parent was about two hours, while the half-life of MHD was about nine hours after the immediate release formulation. A population pharmacokinetic model for Oxtellar XR® was developed in healthy normal adults and applied to pharmacokinetic data in patients with epilepsy. For oxcarbazepine, systemic parameters were scaled allometrically, suggesting that steady state oxcarbazepine exposure will vary inversely with weight.

Special Populations

Elderly

No studies with Oxtellar XR® in elderly patients have been completed [see Use in Specific Populations (8.5)].

Following administration of single (300 mg) and multiple (600 mg/day) doses of immediate-release oxcarbazepine to elderly volunteers (60-82 years of age), the maximum plasma concentrations and AUC values of MHD were 30%-60% higher than in younger volunteers (18-32 years of age).

Comparisons of creatinine clearance in young and elderly volunteers indicate that the difference was due to age-related reductions in creatinine clearance.

Pediatric

Oxtellar XR® is not approved for pediatric patients less than 6 years of age because the size of the tablets are inappropriate for younger children, and has not been studied in patients younger than 4 years of age. A pharmacokinetic study of Oxtellar XR® was performed in 18 pediatric patients with epilepsy, 4 to 16 years of age, after multiple doses. The population pharmacokinetic model suggested that dosing of pediatric patients with Oxtellar XR®can be determined based on body weight. Weight-normalized doses in pediatric patients should produce MHD exposures (AUC) comparable to that in typical adults, with oxcarbazepine exposures ~40% higher in children than in adults [see Use in Specific Populations (8.4)].

Gender

The effects of gender have not been studied for Oxtellar XR®.

No gender-related pharmacokinetic differences have been observed in children, adults, or the elderly with immediate-release oxcarbazepine.

Race

The effects of race have not been studied for Oxtellar XR®.

Renal or Hepatic Impairment

The effects of renal or hepatic impairment have not been studied for Oxtellar XR® [see Use in Specific Populations (8.6, 8.7)].

Based on investigations with immediate-release oxcarbazepine, there is a linear correlation between creatinine clearance and the renal clearance of MHD. When immediate-release oxcarbazepine is administered as a single 300 mg dose in renally-impaired patients (creatinine clearance <30 mL/min), the elimination half-life of MHD is prolonged to 19 hours, with a two-fold increase in AUC. Dose adjustment is recommended in these patients [see Dosage and Administration (2.4) and Use in Special Populations (8.6)].

The pharmacokinetics and metabolism of immediate-release oxcarbazepine and MHD were evaluated in healthy volunteers and hepatically impaired subjects after a single 900 mg oral dose. Mild-to-moderate hepatic impairment did not affect the pharmacokinetics of immediate-release oxcarbazepine and MHD. The pharmacokinetics of oxcarbazepine and MHD have not been evaluated in severe hepatic impairment, and therefore it is not recommended in these patients [see Use in Specific Populations (8.7)].

Pregnancy

Due to physiological changes during pregnancy, MHD plasma levels may gradually decrease throughout pregnancy [see Use in Specific Populations (8.1)]

Drug Interaction Studies

In Vitro: Oxcarbazepine can inhibit CYP2C19 and induce CYP3A4/5 with potentially important effects on plasma concentrations of other drugs. In addition, several AEDs that are cytochrome P450 inducers can decrease plasma concentrations of oxcarbazepine and MHD.

Oxcarbazepine was evaluated in human liver microsomes to determine its capacity to inhibit the major cytochrome P450 enzymes responsible for the metabolism of other drugs. Results demonstrate that oxcarbazepine and its pharmacologically active 10-monohydroxy metabolite (MHD) have little or no capacity to function as inhibitors for most of the human cytochrome P450 enzymes evaluated (CYP1A2, CYP2A6, CYP2C9, CYP2D6, CYP2E1, CYP4A9 and CYP4A11) with the exception of CYP2C19 and CYP3A4/5.

Although inhibition of CYP3A4/5 by oxcarbazepine and MHD did occur at high concentrations, it is not likely to be of clinical significance. The inhibition of CYP2C19 by oxcarbazepine and MHD, is clinically relevant.

In vitro, the UDP-glucuronyl transferase level was increased, indicating induction of this enzyme. Increases of 22% with MHD and 47% with oxcarbazepine were observed. As MHD, the predominant plasma substrate, is only a weak inducer of UDP-glucuronyl transferase, it is unlikely to have an effect on drugs that are mainly eliminated by conjugation through UDPglucuronyl transferase (e.g., valproic acid, lamotrigine).

In addition, oxcarbazepine and MHD induce a subgroup of the cytochrome P450 3A family (CYP3A4 and CYP3A5) responsible for the metabolism of dihydropyridine calcium antagonists, oral contraceptives and cyclosporine resulting in a lower plasma concentration of these drugs.

Several AEDs that are cytochrome P450 inducers can decrease plasma concentrations of oxcarbazepine and MHD. No autoinduction has been observed with immediate-release oxcarbazepine.

As binding of MHD to plasma proteins is low (40%), clinically significant interactions with other drugs through competition for protein binding sites are unlikely.

In Vivo:

Hormonal Contraceptives

Coadministration of immediate-release oxcarbazepine with an oral contraceptive has been shown to influence the plasma concentrations of two components of hormonal contraceptives, ethinylestradiol (EE) and levonorgestrel (LNG). The mean AUC values of EE were decreased by 48% [90% CI: 22-65] in one study and 52% [90% CI: 38-52] in another study. The mean AUC values of LNG were decreased by 32% [90% CI: 20-45] in one study and 52% [90% CI: 42-52] in another study. Therefore, concurrent use of oxcarbazepine with hormonal contraceptives may render these contraceptives less effective.

Calcium Channel Antagonists

After repeated coadministration of immediate-release oxcarbazepine, the AUC of felodipine was lowered by 28% [90% CI: 20-33]. Verapamil produced a decrease of 20% [90% CI: 18-27] of the plasma levels of MHD after coadministration with immediate-release oxcarbazepine.

Other Interactions

Cimetidine, erythromycin and dextropropoxyphene had no effect on the pharmacokinetics of MHD after coadministration with immediate-release oxcarbazepine. Results with warfarin show no evidence of interaction with either single or repeated doses of immediate-release oxcarbazepine.

Applies to oxcarbazepine: oral suspension, oral tablet, oral tablet extended release

General

The most commonly observed side effects were dizziness, somnolence, diplopia, fatigue, nausea, vomiting, ataxia, abnormal vision, abdominal pain, tremor, dyspepsia, abnormal gait, headache, balance disorder, and asthenia. In clinical trials in children aged 1 month to 4 years, the most commonly reported side effect was somnolence.

The side effects most commonly associated with discontinuation of oxcarbazepine (the active ingredient contained in Oxtellar XR) included dizziness, vomiting, nausea, diplopia, and somnolence.[Ref]

Nervous system

The pattern of seizures following oxcarbazepine (the active ingredient contained in Oxtellar XR) discontinuation suggests a rebound phenomenon rather than a loss of therapeutic efficacy.[Ref]

Very common (10% or more): Abnormal gait, ataxia, dizziness, headache, nystagmus, somnolence, tremor
Common (1% to 10%): Abnormal coordination, abnormal EEG, amnesia, ataxia, balance disorder, convulsions aggravated, cranial injury not otherwise specified, dysmetria, gait disturbance, hypoesthesia, impaired concentration, involuntary muscle contractions, speech disorder, taste perversion
Frequency not reported: Aura, depressed level of consciousness, dystonia, extrapyramidal disorder, hemiplegia, hyperreflexia, hyperkinesia, hyporeflexia, hypokinesia, hypotonia, migraine, muscle hypertonia, neuralgia, oculogyric crisis, paralysis, syncope, tinnitus[Ref]

Psychiatric

Common (1% to 10%): Abnormal thinking, agitation, anxiety, apathy, confusion, depression, insomnia, emotional lability, nervousness
Frequency not reported: Aggressive reaction, anguish, anxiety, aphasia, delirium, delusion, dysphonia, euphoria, hysteria, manic reaction, panic disorder, paroniria, personality disorder, psychosis, stupor, suicidal behavior and ideation[Ref]

Pooled analyses of 199 placebo-controlled clinical trials of 11 different antiepileptic drugs lasting a median of 12 weeks showed that patients receiving antiepileptic drugs had approximately twice the risk of suicidal behavior or ideation (0.43%) compared to patients receiving placebo (0.22%). The increased risk of suicidal behavior and suicidal ideation was observed as early as one week after starting the antiepileptic drug and continued through 24 weeks.[Ref]

Dermatologic

Patients with the Human Leukocyte Antigen (HLA) allele B*1502 or HLA-A*3101 may be at an increased risk for Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). The presence of the HLA-A*3101 allele may also increase the risk for drug rash with eosinophilia (DRESS), or less severe acute generalized exanthematous pustulosis (AGEP) and maculopapular rash.

Rare cases of angioedema have been reported in patients after taking the first or subsequent doses of oxcarbazepine (the active ingredient contained in Oxtellar XR) [Ref]

Common (1% to 10%): Acne, alopecia, bruising, increased sweating, purpura, rash
Uncommon (0.1% to 1%): Urticaria
Very rare (less than 0.01%): Angioedema, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis (Lyell's syndrome)
Frequency not reported: Contact dermatitis, eczema, erythematous rash, facial rash, folliculitis, genital pruritus, heat rash, maculopapular rash, photosensitivity reaction, psoriasis, purpura, skin procedure, vitiligo
Postmarketing reports: Acute generalized exanthematous pustulosis (AGEP)[Ref]

Hypersensitivity

Common (1% to 10%): Allergy
Very rare (less than 0.01%): Hypersensitivity (including multi-organ hypersensitivity), anaphylactic reactions
Frequency not reported: Drug rash with eosinophilia and systemic symptoms (DRESS)[Ref]

Rare cases of anaphylaxis have been reported in patients after taking the first or subsequent doses of oxcarbazepine.

Multi-organ hypersensitivity is generally characterized by signs and symptoms such as abnormal liver function tests, rash, and fever. Other organs or symptoms that may be affected include the blood and lymphatic system (e.g., lymphadenopathy, eosinophilia, leucopenia, splenomegaly), liver (e.g., abnormal liver function tests, hepatitis), muscles and joints (e.g., joint swelling, myalgia, arthralgia), nervous system (e.g., hepatic encephalopathy), kidney (e.g., proteinuria, interstitial nephritis, renal failure), and lungs (e.g., dyspnea, pulmonary edema, asthma, bronchospasms, interstitial lung disease).[Ref]

Gastrointestinal

Very common (10% or more): Abdominal pain, nausea, vomiting
Common (1% to 10%): Constipation, diarrhea, dyspepsia, dry mouth, gastritis, rectum hemorrhage, toothache, upper abdominal pain
Frequency not reported: Biliary pain, blood in stool, cholelithiasis, colitis, duodenal ulcer, dysphagia, enteritis, eructation, esophagitis, flatulence, gastric ulcer, gingival bleeding, gum hyperplasia, hematemesis, hemorrhoids, right hypochondrium pain, retching, sialoadenitis, stomatitis, ulcerative stomatitis, dental oral procedure
Postmarketing reports: Pancreatitis[Ref]

Cardiovascular

Common (1% to 10%): Chest pain, generalized edema, hot flushes, hypotension, leg edema
Very rare (less than 0.01%): Arrhythmia, atrioventricular block, hypertension
Frequency not reported: Bradycardia, cardiac failure, cerebral hemorrhage, palpitation, postural hypotension, precordial chest pain, tachycardia[Ref]

Genitourinary

Common (1% to 10%): Urinary tract infection, micturition frequency, vaginitis
Frequency not reported: Decreased/increased libido, dysuria, female reproductive procedure, intermenstrual bleeding, leukorrhea, menorrhagia, micturition frequency, polyuria, priapism, renal pain, urinary tract pain[Ref]

Hematologic

Common (1% to 10%): Lymphadenopathy
Uncommon (0.1% to 1%): Leucopenia
Very rare (less than 0.01%): Agranulocytosis, aplastic anemia, bone marrow depression, neutropenia, pancytopenia, thrombocytopenia[Ref]

Hepatic

Uncommon (0.1% to 1%): Increased blood alkaline phosphatase, increased hepatic enzymes
Very rare (less than 0.01%): Hepatitis
Frequency not reported: Increased GGT, increased serum transaminase[Ref]

Immunologic

Common (1% to 10%): Infection, viral infection
Frequency not reported: Systemic lupus erythematosus[Ref]

Metabolic

Common (1% to 10%): Anorexia, hyponatremia, thirst, weight increase
Frequency not reported: Decrease in T4 with unclear clinical significance, hyperglycemia, hypocalcemia, hypoglycemia, hypokalemia, hypothyroidism, increased appetite, tetany, weight decrease
Postmarketing reports: Increased amylase, increased lipase[Ref]

Hyponatremia associated with signs and symptoms such as seizures, confusion, depressed level of consciousness, encephalopathy, vision disorders, vomiting, nausea, and folic acid deficiency have been reported very rarely.[Ref]

Musculoskeletal

Common (1% to 10%): Back pain, muscle weakness, sprains and strains
Frequency not reported: Musculoskeletal procedure
Postmarketing reports: Decreased bone mineral density, osteopenia, osteoporosis and fractures (long-term therapy)[Ref]

Ocular

Very common (10% or more): Abnormal accommodation, abnormal vision, diplopia
Common (1% to 10%): Blurred vision, visual impairment/disturbance
Frequency not reported: Cataract, conjunctival hemorrhage, eye edema, hemianopia, mydriasis, photophobia, scotoma, xerophthalmia[Ref]

Other

Very common (10% or more): Fatigue, vertigo
Common (1% to 10%): Asthenia, drug intolerance, earache, ear infection not otherwise specified, falling down not otherwise specified, feeling abnormal, fever
Frequency not reported: Feeling drunk, malaise, otitis externa, ptosis, rigors[Ref]

Renal

Frequency not reported: Renal calculus[Ref]

Respiratory

Very common (10% or more): Upper respiratory tract infection
Common (1% to 10%): Bronchitis, chest infection, coughing, epistaxis, nasopharyngitis, pneumonia, pharyngitis, rhinitis, sinusitis
Frequency not reported: Asthma, dyspnea, hiccup, laryngismus, pleurisy[Ref]

Some side effects of Oxtellar XR may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.